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3d66c4e14f
In principle, it is possible to use nolibc for only some object files in a program. In that case, the startup code in _start and _start_c is not going to be used. Add the NOLIBC_NO_RUNTIME compile time option to disable it entirely and also remove anything that depends on it. Doing this avoids warnings from modpost for UML as the _start_c code references the main function from the .init.text section while it is not inside .init itself. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
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/*
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* Stack protector support for NOLIBC
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* Copyright (C) 2023 Thomas Weißschuh <linux@weissschuh.net>
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*/
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#ifndef _NOLIBC_STACKPROTECTOR_H
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#define _NOLIBC_STACKPROTECTOR_H
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#include "compiler.h"
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#ifndef NOLIBC_NO_RUNTIME
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#if defined(_NOLIBC_STACKPROTECTOR)
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#include "sys.h"
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#include "stdlib.h"
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/* The functions in this header are using raw syscall macros to avoid
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* triggering stack protector errors themselves
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*/
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void __stack_chk_fail(void);
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__attribute__((weak,used,noreturn,section(".text.nolibc_stack_chk")))
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void __stack_chk_fail(void)
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{
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pid_t pid;
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my_syscall3(__NR_write, STDERR_FILENO, "!!Stack smashing detected!!\n", 28);
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pid = my_syscall0(__NR_getpid);
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my_syscall2(__NR_kill, pid, SIGABRT);
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for (;;);
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}
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void __stack_chk_fail_local(void);
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__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
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void __stack_chk_fail_local(void)
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{
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__stack_chk_fail();
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}
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__attribute__((weak,used,section(".data.nolibc_stack_chk")))
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uintptr_t __stack_chk_guard;
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static __no_stack_protector void __stack_chk_init(void)
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{
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my_syscall3(__NR_getrandom, &__stack_chk_guard, sizeof(__stack_chk_guard), 0);
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/* a bit more randomness in case getrandom() fails, ensure the guard is never 0 */
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if (__stack_chk_guard != (uintptr_t) &__stack_chk_guard)
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__stack_chk_guard ^= (uintptr_t) &__stack_chk_guard;
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}
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#else /* !defined(_NOLIBC_STACKPROTECTOR) */
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static void __stack_chk_init(void) {}
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#endif /* defined(_NOLIBC_STACKPROTECTOR) */
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#endif /* NOLIBC_NO_RUNTIME */
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#endif /* _NOLIBC_STACKPROTECTOR_H */
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